It is generally known to be desirable to attach a breathing or snorkel tube to the support strap of an underwater mask. In most instances, the breathing tube is attached to the support strap of the underwater mask by means of a retaining strap supported on the breathing tube and including a looped portion, through which the support strap of the underwater mask is passed. However, this attachment arrangement does not provide for easy attachment and removal of the breathing tube to the face mask. This type of attachment is illustrated in U.S. Pat. Nos. 3,603,306; 3,814,090; 4,066,077; and 4,562,836. U.S. Pat. No. 3,051,170 discloses a breathing tube which is provided with a plastic stud to be pressed into adjustment holes in a head strap or band. U.S. Pat. No. 2,317,236 disoloses attaching a breathing tube to the support strap of an underwater mask by means of a clamping strap surrounding the breathing tube and attachable to the support strap of the underwater mask. However, only limited swiveling movement is permitted by these known devices for attaching the breathing tube to the support strap of the underwater mask. Also, these known attachment devices do not permit quick and easy removal and attachment of the breathing tube to the support strap of the underwater mask.